American oil giant ExxonMobil and Russian oil firm Rosneft inked on Tuesday an agreement to jointly search for black gold in the Arctic Sea shelf and Black Sea.

The deal was signed before Russian Prime Minister Vladimir Putin, who said the agreement would permit the Russian state-owned company to develop oil fields in the Gulf of Mexico and Texas.

In turn, Exxon will invest $3.2 billion in opening oil and gas production in the Kara Sea, which is part of the Arctic Ocean. The ice in Kara Sea made drilling in the past difficult, but higher Arctic temperature made the area more attractive to oil firms.

According to Rosneft's estimate, the East-Prinovozemelsky field of Kara Sea has 35.8 billion barrels of oil and 10.3 trillion cubic meters of natural gas, while it placed oil at the Tuapse field at 2.2 billion to 7.2 billion barrels.

Since majority of oil fields in West Siberia are declining, Russia is seeking new sources of unconventional oil resources of the Arctic. However, because of the harsh environment, Russian oil firms have to tap into the expertise of western oil firms such as Exxon, which had drilling experience in Canada's arctic regions.

Rosneft previously had an arctic exploration proposal with British Petroleum, but the deal did not push through in May because of a legal challenge from co-investors in another BP existing Russian joint venture, despite the planned agreement having the blessing of Putin.

Reports said the total value of the projects could be between $200 and $500 billion.